Pilot burner guard



i Jan. 13, 1943.

A. c. SCHICKLER PILdT BUBNER GUA RD Filed Nov. 19,1945

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Patented Jan. 13, 1948 PILOT BURNER GUARD Albert C. Schickler,Cleveland, Ohio, a'ssignor to i The Ajax Thermostatic Controls 00.,Cleveland, Ohio, a corporation of Ohio Application November 19, 1945,Serial No. 629,35

The general object of this invention is to protect the flame of a pilotlight from drafts and from violent air disturbances such as result fromextinguishing or lighting the main burner, and also to prevent foreignparticles such as soot, scale and the like from getting into the burner.

Another object is to retard or impede the velocity of the gas flame,when the gas pressure supply thereto rises to higher than normal, thuspreventing self-extinguishing of the flame. At the same time, it isdesirable for more efiective burning that the velocity pressure betranslated into a comparatively static pressure producing an evenlyburning flame. a

A simple form of pilot burner or pilot ,light which is economical ofgas, provides a desirable mixture and a hot flame is that of the Bunsenburner type.

In such burners variations in gas pressure and velocity of flow mayresult in breaking the continuity of the flame, thus extinguishing it.It is desirable, and therefore one of the objects of this invention, toretard the high velocity of the gas and air mixture for the flame.

A specific object is to so spread the flame as to protect it againstextinguishment.

Another object is to provide such a device for use with a standard formof simple pilot tube burner, and which device may be very cheaplymanufactured, be capable of convenient assembly with the burner tube,and which may hold itself in position by spring tension.

A preferred form of my invention is illustrated in the accompanyingdrawings, in which Fig. 1 shows the present invention associated withthe pilot burner;

Fig. 2 is an enlarged axial section through the pilot burner, with thepresent invention attached hereto;

Fig. 3 is a top plan of the same;

Fig. 4 is a sectional detail on the line 6-4 of Fi 3;

Fig. is a perspective view showing the spring supporting element beforeapplying the cap memher.

In Fig. 1, B designates the main burner such as used for a hot watertank-not shown. This view is merely as illustrative of any use of suchpilot burners.

A gas supply line P leading to the vlcinityof the burner is shown asprovided with threads to receive a threaded nipple, in at the lower endof the burner tube 12 open at its upper end and provided with airopenings l4 appropriately positioned above the opening I! for the gasinlet let.

3Claims. (Cl. 158-113) As normally used, this burner is placed closelyadjacent to the orifices of the main burner B, and its flame normallyrises substantially above the open end of the tube l2. When so usedvarious disadvantages result.

A serious difficulty is that of the violent dis' turbances of air andgas resulting when the main burner is shut off and its flame issuddently extinguished with a violent reaction such as results from theexplosive burnin of gas remaining in the chamber of the main burner.This disturbance often extinguishes the flame of the pilot, and unlessprovision is made for automatically relighting the pilot, whichprovision is often expensive and not always reliable, the main burnermay be turned on and remain on irran unlighted condition.

Extraneous sudden drafts may extinguish the unprotected pilot flame,particularly whenthis flame is burning either very weakly due to low gaspressure, or is burning at a higher position than normal clue to greatermixture stream velocity resulting from high pressure from the jet i5.

In such conditions the pilot flame is particularly vulnerable to beingextinguished. Various guards and re-lighting devices have been devised,obviously adding expense and which are not always found to be reliable.

As indicated in the foregoing stated objects, the present inventionconsists of an exceedingly simple and yet very effective means forprotecting the flame from such extinguishment.

I have found it important to retard the flame velocity, and alsodesirable to spread the flame as is indicated by the broken lines at Fin Figs. 1 and 2. In so retarding the mixing stream for the flame it isstill essential to maintain suflicient mixture and speed of flow foruniform burning around the canopy 25.

One of the present dimculties is that of acid attacking the burnertube,now usually made of brass, and resulting from condensate of flueproducts falling from the surfaces above.

In practice, the tube of the burner is often eaten away in a short timeby the efiects of such condensate. Soot and condensate form a carbonsubstance, sometimes completely blocking the gas burning and mixingpassage of the burner.

To avoid these difliculties, various devices such as special acidresisting tips, for example, lava tips. are mounted at the top of theburner. However, these increase resistance to the flow and adverselyaffect the character of the flame.

A preferred embodiment of my invention comprises a dome-shaped cap,preferably quite flat,

forming the canopy 25 and having an inturned flange 26 adapted-toreceive a. supporting loop 30 of the burner engaging and carryingmember.

This loop is substantially circular and formed to require beingcompressed slightly to permit it to be inserted inside of the flange 26after a manner well known in connection with certain forms of buttonheads, such as campaign buttons. or the lie. 4

It is important that the canopy 25 be properly spaced above the open endof the burner tube 12, and that it may also be securely held in theposition shown in Figs. 1 and 2. To this end I form a tube engagingportion 35 integral with the loop 30 and having an end extension 38engaging the top of the tube l2.

Describing this supporting element more in detail, I prefer to form thecircular head portion 30 and the tube engaging portion 35 of onecontinuous piece of wire. As shown, the loop of the head portion mergeswith an inward radially extending arm 3i, substantially in the plane ofthe loop 30, and from which the wire bends downwardly forming a leg 35substantially right angles to the plane of the head loop. The wirecontinues in a return bend at 3B, and then upwardly forming a leg 31still in a plane substantially normal to the head loop. The end of theleg 31 has a short portion turned sharply outwardly at 38 to form ashoulder or abutment for engaging the upper end of the tube.

As formed, the leg 31 carrying the hooked end 38 is preferably slopedoutwardly from the position it takes when in the tube, in order to givea firm gripping or spring action for engaging the tube.

In Fig. 5, 31a indicates in broken lines the position of the arm 31parallel with the upright leg 38, and the approximate bending or springaction effect of the loop is from the position of the leg 31 shown insolid lines.

The width of the loop 35, 38 and 31 and the comparatively straight legsforming its sides causes an effective tight engagement across thediameter of theupper end of the inside of the tube l2.

The nose portion or bend 38 facilitates the insertion into the tube, andthe length below the limiting hook 38 may be approximately one half ofthe distance from the mixer air openings l4 to the upper end of theburner tube. When in its supporting position, the tube engaging looplies in the plane normal to the plane of-the cap loop 30, and the lengthof the arm 3| is such as to center the loop 30 and the canopy over theburner tube.

The distance from the lower side of the hook 38 I to the loop 30establishes the space, between the tube and flange of the canopy, fromwhich the spreading flame mixture stream flows and is determined formost efl'ective burning with relation to the usual ranges of gaspressure.

The canopy 25 is preferably made of a stainless steel disk toeffectively resist corrosion from condensate and also to resist heat.The supporting wire, being protected by the canopy, may be formed of anymetal capable of retaining its spring action under fairly hightemperatures. In practice stainless steel wire is preferred. I

The cap 25 may be formed of very thin sheet material for purposes ofeconomy. The size of the wire is determined largely by its relativediamin a burner tube of approximately one quarter inch inside diameter,about one thirty-second of an inch diameter wire is satisfactory, and issuflicient to hold the cap rigidly in its spaced and horizontal positionabove the burner.

It will be seen that the supporting wire and flanged caps may be formedand assembled in quantities, and may be conveniently inserted into theburner, whereupon the spring action forces the relatively straight sidelegs 35 and 31 into engagement with the tube, and across its diameter,and to hold the carrying leg 35 against the wall of the tube for adistance sufficient to prevent tipping of-the cap.

In inserting the supporting loop, obviously pressure of the thumb on thecap 25 contracts the bend 36 and the inward movement is limited when thehooked end 38 strikes the top of the tube. Thereafter and until removal,the parts are held firmly in this operative position by spring action ofboth the cap loop and the tube loop.

As above indicated, a serious source of trouble is that of particles ofscale and soot falling from surfaces above the pilot burner. Thecondensate, as stated, is destructive to the burner tube, and the sizeof the protecting canopy should provide sufficient overhang to affordadequate protection from condensate dilppings and falling particles.

A cap approximately flve-eighths of an inch in diameter for a burnertube of half that diameter has been found satisfactory.

From the foregoing description, it will be seen that I have provided avery simple form of guard which has the advantages of being formed bystandard practices, 1. e., punching and flanging a disk and by wireforming, and which when assembled may be inserted with ease, andthereafter may be retained securely in operating position.

Various modifications of the cap and wire support, with its springaction and limiting means establishing the flame mixture passage, may bemade without departing from the spirit and scope of my inventionas'defined in the appended claims.

Having thus described my invention, what I claim is:

1. A burner guard for an upright pilot burner tube comprising adisk-like canopy of a diameter larger than the tube and a support forholding the canopy concentrically of the tube and spaced above the same,said support comprising a single strip of wire formed into a horizontalloop and a downwardly extending arm, a round nose portion and anupwardly continuing arm provided with an outward projection, the armsforming a loop in a plane at right angles to the plane of the firstnamed loop, said projection being spaced from the plane of the firstloop, and means on the dish member for engaging and holding the firstloop under compression.

2. A guard for an upright pilot burner tube comprising a button capsubstantially larger in diameter than the diameter of the tube andhaving an inturned flange, a wire support having a loop yieldinglyengaging within the flange, and having a horizontal portion extendingtoward the center of the loop and integral with a downwardly extendingloop adapted to project into and yieldingly engage the interior of thetube, and a shoulder formed on the latter loop engaging the top of thetube to space the flanged cap member above it to provide flame burningspace between the tube and cap member..

3. A guard for an upright pilot burner tube comprising a flanged capsubstantially larger in diameter than the diameter of the tube, a wiresupport having a loop yieldingly engaging within the flange, an integraldownwardly extending loop adapted to project into and yieldingly engagethe interior of the tube, and a shoulder formed on the latter loopengaging the top of the tube to space the flanged cap member in ahorizontal position above the tube to provide flame orifice spacebetween the tube and cap member.

ALBERT C. SCHICKLER..

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number UNITED STATES PATENTS Name Date Cartter Nov. 24, 1936Snell Apr. 1'7, 1923 Hentshell Dec. 17, 1929 Young Nov. 7, 1916 FOREIGNPATENTS Country Date GreatBritain 1904

